Phage-encoded protein PhiP targets HemA to block heme biosynthesis, suppressing bacterial growth and promoting phage propagation

Bacteriophages encode diverse proteins that subvert host metabolism to promote viral propagation. Elucidating the functions and mechanisms of these proteins not only deepens our understanding of phage-host interactions but also offers new avenues for antibacterial development. Here, we identify PhiP, a protein encoded by the Pseudomonas aeruginosa phage PaoP5, as a potent inhibitor of bacterial growth. Ectopic expression of PhiP leads to impaired cell proliferation and elongation. Co-immunoprecipitation assays identify HemA, the glutamyl-tRNA reductase that catalyzes the first committed step of heme biosynthesis, as a direct interacting target of PhiP. Mechanistically, PhiP-mediated inhibition of HemA disrupts heme production, leading to accumulation of intracellular reactive oxygen species (ROS), heightened sensitivity to hydrogen peroxide, and subsequent growth suppression. Finally, transcriptomic analysis reveals global dysregulation of genes involved in iron uptake and redox homeostasis. Furthermore, infection-based experiments demonstrate that PhiP plays an important role in efficient phage propagation. Collectively, our findings uncover a mechanism by which a phage-encoded protein targets heme biosynthesis to perturb ROS homeostasis, suppress bacterial growth, and promote efficient phage propagation. This work expands our understanding of phage-mediated metabolic manipulation of host bacteria and may inspire novel strategies for antibacterial therapy.